NOUS41 KWBC 231822
PNSWSH

Service Change Notice 12-29
National Weather Service Headquarters Washington DC
120 PM EDT Thu Aug 23 2012

To: Subscribers:
-Family of Services
-NOAA Weather Wire Service
-Emergency Managers Weather Information Network
-NOAAPort
Other NWS partners and employees

From: Eli Jacks
Chief, Fire and Public Weather Services Branch

Subject: Transition of NWS Storm Prediction Center (SPC)
Thunderstorm Outlook (CONUS Only) from Experimental to
Operational Status Effective September 26, 2012

Effective Wednesday, September 26, 2012, at 1700 Coordinated Universal Time (UTC), the SPC Thunderstorm Outlook becomes operational. This product is issued only for the CONUS.

The SPC Thunderstorm Outlook depicts the expected geographic areas of thunderstorms including 10, 40 and 70 percent probabilities in 4 or 8 hour time periods. A 40 percent probability means that given similar environmental conditions, a thunderstorm would be observed at any one location (in either a county or city) within the 40 percent thunder probability area four times out of ten, or 40 percent of the time.

Forecasts of thunderstorms are critical for the protection of life and property since every thunderstorm contains lightning that is a potential killer. The high temporal and spatial resolution of the SPC Thunderstorm Outlook will aid both NWS forecasters and NWS partners in time-sensitive decisions related to thunderstorms and ultimately provide greater safety for the U.S. public.

SPC Thunderstorm Outlook issuance and valid times are:

Issue Time (UTC) Valid Periods (UTC)
———- ——————-
0600Z 1200-1600, 1600-2000, 2000-0000
1300Z 1600-2000, 2000-0000, 0000-0400
1700Z 2000-0000, 0000-0400, 0400-1200
2030Z 0000-0400, 0400-1200
0130Z 0400-1200

The SPC Thunderstorm Outlooks web-based graphic is online at:

http://www.spc.noaa.gov/products/exper/enhtstm/

If you have any questions, please contact:

John Ferree
NWS Severe Storms Services
Norman, OK 73072
[email protected]
405-325-2209

National Service Change Notices are online at:

http://www.weather.gov/os/notif.htm

$$